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(No Model.) 2 Sheets-Sheet 1.

C. E. EELCH,

MEANS EOE VARYING CANDLE POWER CE INCANDESCENT ELECTRIC LAMPS.

Patented Jan. 4,1898.

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(No Model.) 2 Sheets-Sheet 2.

C. E. EELCH. MEANS EUR VARYING CANDLE POWER OE INCANDESCENT ELECTRICLAMPS. 180.596,582. Patented Jan. 4,1898.

ll/7149.55 es. l lvwedor UNITED STATES PATENT OFFICE.

CIIARLES E. FELCH, OF NATICK, MASSACHUSETTS, ASSIGNOR OF ONEJIALF TOOLIVER A. FELCI'I AND IVALTER L. FELCII, OF SAME PLACE.

MEANS FOR VARYING CANDLE-POWER F INCANDESCENI ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 596,582, dated January4,1898.

Application filed Juno 21, 1897.

To all whom t may concern:

Be it known that I, CHARLES E. FELCI-I, of Natick, in the county ofMiddlesex and State of Massachusetts, have invented an Improvement inMeans for Varying the Candle-Power for Incandescent Electric Lamps, ofwhich the following description, in connection with the accompanyingdrawings, is a specifica tion, like letters and gures on the drawings 1orepresenting like parts.

This invention has for its object the production of novel means wherebyby a local change in voltage not exceeding the rated voltage of thecircuit the candle-power of an individual incandescent electric lamp maybe varied irrespective of other lamps in the circuit, so that anydesired degree of brilliancy may be attained within the ratedcandle-power of the lamp.

By my invention I am also enabled to increase the candle-power of thelamp above its rated power by using a lamp of lower rated voltage thanthe rated voltage of the circuit, though such increase of candle-powerwill dez 5 crease the life of the lamp.

In accordance with my invention I include in circuit between the lineand the lamp-filament a permeable resistance medium adapted to beentered to a greater or less depth by an electrode also included in thecircuit, means being provided to effect relative movement of theelectrode and resistance medium to thus vary the resistance and therebyregulate the candle-power of the lamp.

Preferably I apply my invention to a lampsocket as the most convenientand economical means of individually controlling the lamps.

Various novel features of my invention will be hereinafter fullydescribed, and particularly pointed out in the claims.

Figure l is a front elevation of a socket for incandescent electriclamps embodying one form of my invention with a lamp applied thereto.Fig. 2 is an enlarged central vertical section with a portion of thelamp broken off. In Figs. l and 2 the parts are in such relativeposition as to give about one-half the full candle-power of the lamp.Eig. 3 is a similar View showing the parts in position assumed when thecircuit is broken and the light turned off. Fig. 4 is an elevation ofthe serai No. 641,551. (No man.)

inner shell or casing removed. Fig. 5 is a top or plan view thereof.Ifig. G is a horizontal sectional view taken on the line 6 G, Fig. e.Fig. 7 is a lower end View of the carrier for the resistance medium andthe inner casing, the latter being shown in section. Eig. S is a diagramillustrating the circuit connections in the socket and between the lineand the lamp-filament.

Similar letters and iigures of reference indicate corresponding parts.

A represents an external metallic shell or casing provided with ahorizontal slot a, Figs. l and 2, and an inner metallic casing or shellB is mounted in and adapted to be partially rotated within the casing Aby a handle h, extended through the horizontal slot a and secured to theinner casing B. A suitable annulus or washer c, of asbestos or othernonconductor of heat and electricity,is interposed between the twocasings and is packed in an annular chamber formed by the recessed oroutwardly-bent portion A oi' the outer casing.

C and D are two members of non-conductive material, neither of which hasa rigid connection with the inner casing B, but both of which are withinit and separated from each other by a suitable space.

The upper member or holder C has rigidly secured to it a rod LZ, whichextends down through the carrier D and through a disk d", ofnen-conductive material, mounted on the lower end of the inner casingand covering a large opening B in said end. The lower end of this rod isprovided with an ordinary scrcw thread d', by means of which the lamp Sis attached in usual manner.

The holder C is transversely recessed at its Lipper end to leave apassage C' between the upturned portions CX of said holder, (see Figs.2, 3, and 5,) the portions CX occupying the space in the outer caseabove the holder, while the passage C' permits the wires X and Y, whichconnect with the line, to extend through la suitable opening A10 in theupper end of the outer casing down to bindinge screws on contact platesf and g, both of which are secured to the top of the holder C on thebottom of the passage, the plate g being in electrical connection withthe rod d. Screws C connect the outer casing A with.

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the parts C of the holder C. lines, Fig.

The non-conductive carrier D is bored from theunder side upwardpreferably at a number of points, such bores or recesses E ex tending upvertically and part way through the carrier, ten such recesses beingherein shown. (See Figs. 2, 3, G, and 7.) At the lower end of each otthese recesses a small metallic plug` is inserted, consisting of aeireular base F, Afrom which extend upwardly a pair of spring-jaws FCBetween these jaws and resting on the base I prefer to place a loosemass of granulated copper' Il, while above the jaws and the granulatedcopper in each recess is a loose mass of permeable resistance materialK, preferably granulated flake graphite,which extends to a pointsomewhat below the upper end of the recess.

Rigidly secured to the holder C are a num ber of vertical metallic rodsor electrodes, ten bein g'shownin the drawings. These rods correspondwith and extend into the recesses E. The nine electrodes L have theirupper ends secured within the holder C, and the electrode L extendsentirely through said holder and is electrically connected with theplate f by a short wire 75. (See Fig. 8.)

On opposite sides of the inner casing B are diagonal slots P, (see Figs.i and 6,) into which extend screws or pins R, which project horizontallyfrom opposite sides of the carrier D.

It will readily be seen that it' the handle h be moved laterally in theslot a of the outer casing it will rotate the inner casing B, to whichit is secured, and the rotation of the lat-ter will, by travel of thescrews or pins R in the diagonal slots I), cause the carrier D to beraised or lowered in the casing E, according to the direction in whichthe handle Z) is moved. In Figs. l and 2 the handle b is about in thecenter of the slot c, and the rods L extend down into the resistancemedium K to about one-halt' the depth of the same. If the handle l) weremoved to the right as far as the slot a will allow, the rotation of theinner easin g in the same direction would lift the carrier D until theelectrodes L penetrated the resistance medium a greater distance andtheir lower ends would contact with the granulated copper ll between thejaws F. Should, however, the handle l) be moved as far as possible tothe left, the inner casing would be rotated toward the left and lowerthe carrier D until the lower ends of the electrodes L would be liftedentirely out ot the resistance medium.

The metallic plugs F are electrically eennected in pairs-that is to say,a pair oi plugs is connected together, the next pair of plugs isconnected together, but not connected with the first pair, and so on, asshown by the wires U in Fig. 7 and diagrammatically in Fig. `8. Theelectrodes L L are also electrically connected in pairs, but the pairsdo not correspond or coincide with the connected (See dotted pairs ofplugs-that is to say, one electrode over one of a pair ofelectrically-connected plugs is electricallyconnected with the adjacentelectrode of the next pair of connected plugs, as seen by broken linesin Figs. 2 and 5 and the wires V in Fig. 8.

New, supposing the parts to be in the position indicated in all thefigures except Fig. 3 and the current passing from the line through thewire X, the current will pass from said wire through the contact-platej', thence to and down through the electrode L and through theresistance medium K below the end of said electrode to the copper Il,thence through the corresponding metallic plug F and through aconnecting-wire U to the next plug F, (see Fig. 8,) up through thepowdered copper and resistance K and through a con necting-wire V to thenext electrode L, and alternately through the electrodes L andresistance K to the last electrode L in the series of electrodes, andthence through a wire 7L, Fig. S, to a metal ring ll5 (shown in section,Figs. 2 and 3) on the holder C in contact with the inner casing ll. Fromthe casing D the current passes to a metallic contact-ring orcommutating-disk B on the lower end of the inner casing and through thelamp-llament S to the lower end oi' the rod d, and from said rod throughthe contact-plate g to the wire V. lf the electrodes are out ot theresistance medium, the current will not enter the socket and the lightgoes out. rlhe deeper the electrodes extend into the resistance mediumthe less is the resistance to the current, while the less the electrodesenter therein the greater the resistance, inasmuch as the masses ofgraphite or other permeable resistance medium between the lower ends orthe electrodes and the copper ll are deeper and greater. Hence if theelectrodes are extended into the resistance medium the light furnishedby the filamentv will increase until they reach the copper ll or themetallic plugs, when the candie-power is the greatest, the metaloltering the least resistance to the current. As the electrodes arewithdrawn the light decreases in intensity until, when the electrodesare entirely withdrawn, as in Fig. 3, the light will be extinguished. Itis evident therefore that by moving the handle l) in the slot d thelight may be regulated with absolute exactness an d the candle-power bemade greater or less at will. As a consequence the consumer will pay fora low light only when such a light is desired, as -the meter will onlyregister the amount of electricity employed.

lt will be obvious from the foregoing description that when thecandle-power of the lamp is decreased there will be some heating of theresistance medium and the adjacent parts, and in order to prevent suchheating from being noticed at the exterior of the socket l make use of anon-heat-condueting material, such as asbestos, surrounding the innercasing or shell at about the point where greatest heating would occur.The ai r-spaeo IOO IIO

- reduce wear on the electrodes to zero.

between the inner and outer casings also serves to dissipate or scatterthe heat which may be generated within the socket.

The upper commutator-ring H5 maintains a continuous electricalconnection between the inner casing B and the series of electrodes.

I prefer to use flake graphite as the permeable resistance medium, as itis cheap, and a less quantity is required to adapt the device to agreater range of voltage of the lamp-cir cuit than Would be requiredwith some other medium, such as mercury, wire, dsc. The graphite isincombustible and practically nonfusible and it will not vary in densityby use. Furthermore, when the candle-power of the lamp is decreased andthe temperature of the resistance medium increased I have found that byusing flake graphite such heating will not cause any appreciable changein the candle-power of the lamp. The lubricating character of thegraphite also acts to practically The graphite is readily entered by theelectrodes, it is not liable to pack down, and it prevent-s a too suddenvariation in brilliaucy of the light when the same is regulated. As thecircuit is broken in a number of places, as herein shown, there islittle danger of sparking.

The split plugs F F' are so formed in order that they may yield safelyunder any expansion caused by heating of the adjacent parts. l Themembers C D maybe of porcelaimiiber, or any other non-conductive andnon-combustible material.

Having fully described my invention, what I claim, and desire to secureby Letters Patent, ism

l. In a socket for incandescent electric lamps, a rotatable shell, acarrier of insulating material mounted therein and having a recess, apermeable resistance medium held in said recess, an electrode adapted tobe extended into said medium, and means connected with and actuated byrotation of the shell to effect relative movement of said electrode andcarrier within the shell, and there-v by extend the electrode into theresistance medium to different depths, said medium and electrode beingin electrical circuit with the lamp-filament, and the line.

2. In an electric-incandescent-lamp socket, a fixed outer shell, arotatable-inner shell, a carrier of non-conductive materiallongitudinally movable in said inner shell and provided with a pluralityof recesses, permeable resistance material in said recesses, anonconductive holder secured in the upper end of the inner shell,rod-like electrodes extending from the holder into the several masses ofresistance material, connections between the carrier and inner shell,whereby rotation of the latter moves the carrier toward or from theholder, to thrust the electrodes into the resistance material todifferent depths and to withdraw them therefrom, and means to effectrotation of the inner shell, said electrodes and masses of resistancematerial be ing in electrical circuit with the lamp-fila ment and theline, whereby the current will pass through the electrodes and masses ofresistance alternately.

3. In anincandeseent-electric-lamp socket, a carrier of non-conductivematerial provided with recesses containing a permeable resist- -ancemedium; a non-conductive holder provided with a series of metallic pinsor rods extending therefrom freely into said recesses in the carrier;and means supported by and operated from the exterior of the socket toeffect relative movement of said carrier and holder, whereby all of saidrods or pins may be simultaneously thrust into the resistance materialto different depths or withdrawn therefrom, said resistance material androds or pins being in electrical circuit with 'the filament of the lamp,substantially as described.

l. In an electric-incandescent-lamp socket, the carrier D ofnonconductive material bored vertically from the under side to provideparallel recesses E metallic spring-co11 trolled plugs set in the lowerportions of said bores and supporting portions of granulated copper;masses of powdered or granulated flake graphite within said bores andsustained bythe plugs; a holder C of non-conductive material, electrodesformed as rods or pins extending from said holder through a portion ofthe carrier D and into the graphite; and means for reciprocating thecarrier toward and from the holder, whereby said rods or pins may bethrust into the graphite to different depths and withdrawn therefrom,said rods and metallic plugs being in electrical circuit with thefilament of the lamp andthe line, substantially as set forth.

5. In an electric-incandescent-lamp socket, in combination, an outercasing A provided with a horizontal slot a; an inner casing B providedwith diagonal slots P; a handle on the inner casing and extendedoutwardly through said slot a and adapted to rotate the inner casing;the carrier D of non-conductive material, recessed vertically from theunder side to form a plurality of recesses; masses of resistancematerial sustained in said recesses 5 peripheral pins extending radiallyfrom said carrier D into the diagonal slots aforesaid, and the holder Cmade of non-con ductive material and provided with downwardly-projectingelectrode rods or pins extending into the resistance material, the

holder and carrier being mounted within the inner casing, saidelectrodes and resistance material being in electrical circuit with thefilament of the lamp and the line, substan tially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnessesA CHARLES E. FELCll.

Witnessess JOHN C. EDWARDS, AUGUSTA. E. DEAN.

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